An anastomosis is the joining of luminal structures within the body by way of collateral channels when the natural channels are blocked. One common example is a colonic anastomosis in which two portions of the colon are joined together. Creating an anastomosis is a critical step in many surgical procedures, including those that address diseases as wide-ranging as cancer and obesity. For example, a gastrojejunostomy anastomosis may be created between the stomach and the jejunum to treat blockages in the duodenum or for malabsorption, e.g., gastric bypass surgery. An entero-enteral anastomosis may be created for jejuno-jeunal bariatric purposes, a colon to ileum anastomosis may be created for bypassing colorectal cancer, and a biliary duodenal anastomosis may be created between the bile duct and the duodenum above a malignant or benign obstruction in the bile duct.
An anastomosis may be created using open surgical procedures requiring the patient to be placed under general anesthesia, or using endoscopic or laparoscopic procedures that are much less invasive and often do not require general anesthesia. In addition to traditional cutting and stapling or suturing procedures, compression or suture-less techniques can also be used to create an anastomosis. A compression anastomosis is formed by necrotic ischemia caused by the occlusion of the blood supply to the tissue. Compression is applied to the tissue using one or more masses to sandwich the tissue in the target area. One compression anastomosis technique employs a compression button that erodes through the bowel wall over several days because of ischemic necrosis resulting in a leak-free anastomosis. Another suture-less compression anastomosis technique employs a bio-fragmentable ring to create an anastomosis in the bowel.
Other anastomoses may be created using flexible endoscopy techniques employing spring compression buttons. Flexible endoscopy anastomosis techniques may employ ultrasonography techniques when access is limited to a single endoscopic lumen. Magnets also have been used to form compression anastomoses when access is possible to both transgastric lumens or by passing a device through the jejunum. Magnetic compression gastroenteric anastomoses may be performed by introducing magnets perorally with endoscopic and fluoroscopic guidance and mated across the gastric and jejunal walls. Compression anastomoses may be formed between bile ducts using magnets following duct stenosis in liver transplant patients.
In many cases, the anastomosis fistula becomes strictured, or narrowed, over a period of time. This may be due to the method used to create the anastomosis fistula, e.g., using small magnets results in a small fistula between body lumens, or may be the result of the natural healing behavior of the body, e.g., tissue building up around the anastomosis fistula. In some cases, the strictured anastomosis is not large enough to effectively pass contents between the two body lumens. As a result, there is a need for methods of enlarging a strictured anastomosis fistula to more effectively pass contents between the two body lumens. Various methods exist in the prior art, including the use of balloons or stents to dilate and retain the size of an anastomosis fistula. However, these methods can be complicated and risk tearing the fistula. Accordingly, there remains a need for improved methods for enlarging an anastomosis.